It is very desirable to be able to collect samples of sewage from a wide variety of different sewage treatment reservoirs to determine whether the sewage is being treated properly, has the desired qualities, etc. This is true with respect to a wide variety of sewage parameters, but particularly for determining alkalinity, such as described in U.S. Pat. No. 5,094,752, the disclosure of which is hereby incorporated by reference herein.
There are a number of commercially available systems that allow samples to be collected and analyzed, however a major drawback associated with such systems is low dependability and high maintenance. Typical sample collection and analysis systems requiring servicing as often as hourly or daily, and often do not give the user confidence in the reliability of the quality and quantity of the samples, making suspect the results of the analytical procedures that are performed.
According to the present invention, a sample collection and analytical system, and a method of collecting and analyzing sewage samples from a sewage treatment reservoir, are provided which greatly enhance the dependability, reduce the maintenance, and increase confidence in the quality and quantity of sample analysis, as compared to the prior art. Utilizing the present invention, approximately a 30 day service schedule may be expected, with high quality results throughout the entire between-service times.
According to the present invention, the sewage slurry, which often has stringy material in it that will reconstitute itself unless shredded, is acted upon by a grinder pump. The grinder pump breaks down the rags, plastics, strings, or other organic solids into fine pieces, preventing plugging of the system. The ground up sewage slurry is then passed by the grinder pump with a high velocity through a filter assembly, the high velocity flow producing a scouring effect on the inner filter walls thus greatly reducing cleaning and maintenance. The filtrate is transferred in a continuous flow through a black (to prevent algae growth) conduit to a rotameter, to a transparent sample collection reservoir, and ultimately through a solenoid controlled valve to an analyzer. The sample collection reservoir has a continuous overflow waste return means associated with it for returning overflowing filtrate to the sewage treatment reservoir. Continuous overflow ensures the constant availability of a fresh representative sample for the analyzer.
A plurality of the assemblies described above are connected together to a single analyzer, or to multiple analyzers. The solenoid valves are connected through a manifold to the analyzer, and a computer controls the analyzer and the solenoid controlled valves, and receives data from the analyzer. The analyzer may analyze any quality or qualities of the filtrate, such as alkalinity.
The method of the invention comprises collecting and analyzing sewage samples from sewage treatment reservoirs, comprising the steps of automatically: (a) At a plurality of different points in a sewage treatment reservoir, grinding up sewage solids, including stringy material, to prevent clogging of sewage transporting conduits. (b) Passing the ground sewage solids in a water slurry through a flow through filter having interior filter surfaces at such a velocity and volume as to scour the interior filter surfaces, while producing filtrate. (c) Returning the sewage slurry from the filters to the sewage treatment reservoir. And, (d) analyzing filtrate from the filter to determine properties thereof. Step (b) is preferably practiced by passing the slurry at about 35 gallons per minute through an approximately one inch internal diameter filter, which ensures the scouring action.
It is the primary object of the present invention to provide for the high dependability and low maintenance collection and analysis of high quality, representative samples associated with a sewage treatment reservoir. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.